Motor-driven rotary telephone switching mechanism



July 22,1958 F. SOMMER m, 2,844,655

MOTOR-DRIVEN ROTARY TELEPHONE SWITCHING MECHANISM Filed Jan. '18, 1952 2SheetsSheet 2 Fig.2

United States Patent MOTOR-DRIVEN ROTARY TELEPHONE SWITCHING MECHANISMFriedrich Sommer, Berlin-Nikolassee, and Helmut Hofmann and Hans Eder,Munich, Germany, assignors to Siemens & Halske Aktiengesellschaft,Munich, Germany, a German corporation Application January 18, 1952,Serial No. 267,070 Claims priority, application Germany March 14, 1951 6Claims. (Cl. 179--27.51)

This invention is concerned with the arrangement and construction of camcontrolled contacts for governing certain operations of a motor drivenrotary telephone switch of the type described in copending applicationSer. No. 269,224, filed January 31, 1952, now Patent No. 2,701,824,issued February 8, 1955.

A switch of this type is provided with a drive motor comprising twoalternately operable drive magnets for rotating in a steady continuousmotion an armature which in turn rotates a drive wheel provided with acarrier from which extend wipers for selective engagement with bankcontacts. Drive motors of this kind are described in Patents Nos.2,002,546 and 2,654,846. The operative actuation of the drive magnets tocause rotation of the armature and therewith rotation of the drive wheelto rotate the wipers is governed by contacts controlled by the shaft onwhich the armature is mounted. The stopping of such a switch is effectedby simultaneously energizing both drive magnets. An example of a controlcircuit for the drive magnets of such a motor-driven rotary switch maybe had from Patent No. 2,691,699.

Certain steps or positions of such a switch, which may be used as agroup selector or as a connector, or, rather to say, certain contactsthereof are used for marking intermediate resting or control positionsso as to govern the switch in its operation with respect to its bankcontacts. It must be considered in this connection that such a switch ispurely a rotary switch as distinguished from switches, for example, ofthe Strowger type, in which the wipers are raised vertically to adesired level (decade-tens selection) and thereafter rotated in suchlevel to establish engagement with desired bank contacts (unitselection). In the motor-driven switch, there may be several sets ofvertically successively disposed wipers for selective engagement withassociated sets of bank contacts disposed similarly in verticallysuccessive groups. Accordingly,

- there is no vertical raising of the wipers but only rotation thereof.It the switch is used as a group selector, the set of wipers coactingwith a certain group of bank contacts are responsive to dial pulsesrotated to a position in engagement with the first set of contacts insuch group and thereafter hunt for idle bank contacts (trunk) in suchgroup. If the switch is used as a connector, the wipers are rotated tothe desired group of bank contacts and thereafter rotated in such groupto select the desired line, both phases of rotation being controlled bydial pulses. Special controls are accordingly required in 'order tosynchronize the operation of the switch with the transmission of dialpulses. There are also required normal contacts, that is, fordesignating the normal position of the switch so as to control thehoming operation thereof. All these contacts which are necessary forcontrolling the wiperposition-ing operations of the switch are governedby one or more cam wheels which rotate in synchronism with the drivewheel of the switch. The functions of some of these cam controlledcontacts may in a descriptive sense be likened to the functions ofthe-vertical off-normal and the rotary olf-normal contacts in a Strowgerswitch.

The cam contacts were previously actuated directly by the cam wheels andwere accordingly disposed tangential thereto. Access to the contactpoints and adjustment thereof is in such prior structures difficult, andthe proper operation of the contacts cannot be easily observed.Ohattering of the contacts also occurs, due to the direct actuationthereof by the cam wheels.

The object of the invention is to avoid these drawbacks by arranging andconstructing the contacts controlled by the cam wheels (decade contacts,control position contacts and normal contacts) in the switch frame in apar ticularly simple and easily accessible manner radial of the switchaxis and by actuating them through the medium of cam levers which arepivotally disposed on the switch frame and operated by associated camwheels. The contacts are thereby so arranged that the solderingterminals face inwardly, while thecontact points face outwardly. Thecontacts are disposed on an arcuate, approximately semi-circular lineopposite the 'bank contacts of the switch. The cam controlled lever,which actuates the normal contacts, may also be employed as a pointedcoacting with an indicia-carrying member for indicating the switchpositions. The indicia member is preferably formed in the manner of afrusto-conical ring so as to facilitate the observation of the operatingpositions of vertically superposed switches, and particularly theobservation of switches disposed in lower levels.

The various features of the invention will become ap parent from adescription of the accompanying drawings, in which Fig. .1 shows asimplified perspective view of the driving mechanism of a switch; and

Fig. 2 is an elevational bottom view thereof.

In the switch frame 1 is disposed the stationary shaft 2. Rotata'blyjournalled on the shaft 2 is the drive wheel 3 on which is fixed thewiper carrier 4. The drive wheel 3 is rotated in the direction of thearrow by the stepping motor having the field coils '11. These fieldcoils operate, an armature, as described before, and the armaturerotates upon actuation, a suitable gear which meshes with gear teethprovided on the drive wheel 3 peripherally thereof.

The wiper carrier 4 is in its upper portion shaped in the manner of across bridge, the shaft 2 extending through holes formed in the crossedparts thereof. The wipers 6, which are fastened on the carrier 4, sweepover the bank contacts (not shown), and their ends 7 are conductivelyconnected with slip rings 8 which are disposed on the shaft 2 andconnected by conductors included in the cable 9 (Fig. 2). On the drivewheel 3 isdisposed the cam wheel 10 forming the earns 11, 12 whichcoact, during the rotation of the drive wheel 3, with the cam levers 14,15, 16. If desired, several separate cam wheels may be provided, one foreach of the cam levers. As may be seen from Fig. 2, these cam levers arepivotally mounted on the pins 17, 18 and 19, respectively, which aredisposed on the underside of the switch frame. Angular displacement ofthe cam levers by the associated cams causes operation of the coactingsets of contacts 20, 21 and 22, respectively. These contacts arefastened on the underside of the switch frame by screws 29 and extend indirections radial of the switch axis. The soldering terminals 1 of thecontacts face inwardly, and the contact points face outwardly. Thefunctions of the various sets of contacts 20, 21, 22 will depend on theparticular switch.

The switch frame is provided with ribs such as 24, forming a protectiverecess for receiving the contacts. The cable carrying the conductorsextending from the slip rings 8 and from the control contacts may alsobe disposed in this recess.

In order to indicate in a simple manner any operating position in whichthe switch may be, there is provided the indicia ring 25 which isrigidly connected with the drive wheel 6 coaxial therewith. This indiciaring is frusto-c-onical in shape, forming a downwardly sloping outsidewall. The cam lever 14, which operates the normal contacts, also servesas a pointer for indicating the switch positions in coaction with theindicia ring 25.

The bushings 26, 27 are provided for receiving ad- 'justing pinsassociated with the mounting frame (not shown). Screws 2% serve forconnecting the switch with the mounting frame.

Changes may be made within the scope and spirit of the appended claims.

We claim:

1. In a motor-driven rotary telephone switch having a frame and having adrive wheel rotatably mounted on said frame and a motor for rotatingsuch drive wheel to rotate wipers relative to bank contacts disposed onone side of said frame, said drive wheel carrying cam means; a devicefor controlling the operation of said motor, said device comprising aplurality of sets of control contacts, means for mounting said controlcontacts on the underside of said frame, an operating lever for each setof control contacts, and means for pivotally mounting each operatinglever for operative actuation by said cam means.

2. A structure and cooperation of parts according to claim 1, whereineach set of control contacts comprises contact spring means havingterminals facing radially inwardly and contact points facing radiallyoutwardly of said switch.

3. A structure and cooperation of parts according to claim 1, wherein arecess is formed in said frame on the underside thereof for receivingsaid sets of control contacts.

4. A structure and cooperationof parts according to claim 1, whereinsaid sets of control contacts are disposed opposite the bank contactsalong an arcuate approximate semi-circular line radially spaced from theswitch axis.

5. A structure and cooperation of parts according to claim 1, whereinone of said sets of control contacts constitutes the oil-normal contactsof said switch, a circular indicia-carrying member rotatable with saiddrive wheel, the operating lever for operating said off-normal contactscooperating with said indicia-carrying member to indicate the positionof the wipers with respect to the bank contacts of the switch.

6. A structure and cooperation of parts according to claim 1, whereinsaid sets of control contacts are disposed within a recess formed insaid frame on the underside thereof and extending opposite the bankcontacts along an arcuate approximately semi-circular line radiallyspaced from the switch axis, each set of control contacts comprisingcontact spring means having terminals facing radially inwardly andcontact points facing radially outwardly of said switch, a circularindicia-carrying member rotatable with said drive wheel, one of saidoperating levers forming a pointer for cooperation with saidindicia-carrying member to indicate the position of the wipers withrespect to the bank contacts of said switch.

References Cited in the file of this patent UNITED STATES PATENTS1,117,553 Craft Nov. 17, 1914 1,161,126 Grabe Nov. 23, 1915 1,375,762Thompson Apr. 26, 1921 1,636,170 Chaplin July 19, 1927 1,978,700 Doringet al. Oct. 30, 1934 2,701,824 Ulrich et al. Feb. 8, 1955

